1-4
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In password authentication, the client encrypts the username and password, encapsulates them
into a password authentication request, and sends the request to the server. Upon receiving the
request, the server decrypts the username and password, compares them with those it maintains,
and then informs the client of the authentication result.
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The publickey authentication method authenticates clients using digital signatures. Currently, the
device supports two publickey algorithms to implement digital signatures: RSA and DSA. The client
sends to the
server a publickey authentication request containing its user name, public key and
algorithm. The server verifies the public key. If the public key is invalid, the authentication fails;
otherwise, the server generates a digital signature to authenticate the client, and then sends back a
message to inform the success or failure of the authentication.
Session request
After passing authentication, the client sends a session request to the server, while the server listens to
and processes the request from the client. If the client passes authentication, the server sends back to
the client an SSH_SMSG_SUCCESS packet and goes on to the interactive session stage with the
client. Otherwise, the server sends back to the client an SSH_SMSG_FAILURE packet, indicating that
the processing fails or it cannot resolve the request. The client sends a session request to the server,
which processes the request and establishes a session.
Data exchange
In this stage, the server and the client exchanges data in this way:
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The client encrypts and sends the command to be executed to the server.
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The server decrypts and executes the command, and then encrypts and sends the result to the
client.
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The client decrypts and displays the result on the terminal.
SSH Server and Client Configuration Task List
Many devices can act as the SSH server and client. This document describes two cases:
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The 3Com switch acts as the SSH server to cooperate with software that supports the SSH client
functions.
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The 3Com switch acts as the SSH server to cooperate with another 3Com switch that acts as an
SSH client.
Complete the following tasks to configure the SSH server and clients:
Server
Client
Server side
configuration
Client side configuration
An 3Com switch
Software that
supports the SSH
client functions
Configuring the SSH
Server
Configuring an SSH Client that
Runs SSH Client Software
An 3Com switch
Another 3Com switch
Configuring the SSH
Server
Configuring an SSH Client
Assumed by an
SSH2-Capable Switch
Configuring the SSH Server
The session establishment between an SSH client and the SSH server involves five stages. Similarly,
SSH server configuration involves five aspects, as shown in the following table.
